Ask a Climatologist: How does a hot Pacific Northwest affect Alaska?

Ariel Svetlik washes dirt of her mountain bike after a sunny ride in Juneau on June 19, 2021. (Rashah McChesney/KTOO)

There have been some pretty incredibly high temperatures recently in the Pacific Northwest, and Southeast Alaska has shared in that heat, too, with some local, daily record highs.

But in most of Southcentral, if you ask somebody about June, they’re likely say it was cool.

And that would not be true, says National Weather Service climate researcher Brian Brettschneider.

That’s because Brettschneider has seen the data, which shows June in Southcentral was actually a little warmer than normal.

He joined Alaska Public Media’s Casey Grove for another Ask a Climatologist segment.

Listen:

The following transcript was edited lightly for length and clarity.

Brian Brettschneider: So here in Anchorage, out of 70 years of data at the airport, it was the 19th warmest June. So we were warmer than normal. In fact, we were in the top third of warm years. And statewide, we were about six-tenths of a degree warmer than normal.

Fairbanks was about two degrees above normal for the month. Juneau was right at normal for the month. And it’s been interesting because a number of people have come to me and said, “Why is it so cool this June? What’s going on? And when are we going to get our warmth?” And I keep reminding people, “Hey, it’s been a warmer than normal month. And, in fact, we would consider this significantly warmer than normal.” And people have a hard time grasping that.

Casey Grove: Is that just that people have gotten used to it being warmer in general in the last few years, and our memories aren’t good enough to remember back?

Brettschneider: I think that’s right. I think because in the last eight or nine years — probably about five of those years have been really high-end warm summers, record-warm summers. And so that kind of becomes our so-called new normal. And when we deviate from that, we kind of feel like it’s a big change in the other direction, even though we’re in the top 20-25% of warm Junes for Anchorage.

Grove: Let’s talk about the more recent heat in Southeast Alaska, which I understand is very related to the heat in the Pacific Northwest, where you saw places well above 100 degrees. Tell me about that.

Brettschneider: So just incredible, off-the-charts, record-high temperatures in Portland, Seattle, parts of Idaho, Montana and British Columbia. In Lytton, British Columbia, they set the national record three days in a row. And then, unfortunately, that town burned down in a wildfire two days later.

Southeast Alaska was just barely on the periphery of that. So that was ostensibly caused by a huge dome of high pressure situated right at the U.S.-Canadian border. And that’s a very unusual position for it. Normally, that’s going to be much farther to the south. And in Southeast Alaska — where we launch weather balloons from Annette Island, near Metlakatla — they actually recorded some of their all-time warmest temperatures, their highest freezing-level on record. And there were some associated high temperatures. So Ketchikan set record high temperatures a few days, in the 80s. Even Hyder, on the border next to Stewart, British Columbia, got over 90 degrees. But it was fairly localized. Juneau did get over 80 degrees two days in a row. So they were just kind of on the edge of it and felt a glancing blow of it. But certainly warm, and a record-warm in Southeast.

Grove: Is the fact that it’s so hot there, does that have impact on what is happening here in that, you know, it might be cooler on this side of that blocking pattern?

Brettschneider: You’re right. The atmospheric flow moves in kind of waves around the globe, at different latitudes. And they generally form about 5 to 7 waves across our latitude — 50 to 60 degrees north. And wherever the jet stream kind of shoots up, it has to come back down somewhere else, so it can conserve momentum, conserve what’s called vorticity. So on one side of that wave it’s going to be warm and on the other side it’s going to be cool. But the fact that there’s a big high pressure there, upper level, means there has to be a low pressure, upper level, somewhere else. And we’ve been in that sweet spot.

Alaska Public Media

Alaska Public Media is our partner station in Anchorage. KTOO collaborates with partners across the state to cover important news and to share stories with our audiences.

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